The darkest hour …
Is just before the dawn.
Animated diagram of the winter and summer solstice
And especially if that pre-dawn period occurs on December 20th. Not to worry: Daylight hours start to get longer starting on the 21st. The reason: The earth rotates around the sun on a 23.4° tilt. That’s what gives us earthlings our four seasons, or if you live in south Florida, it’s two (i.e. the south Florida exception). To be technically correct, seasons are celestially-defined. Thus, even though they are subtle, south Florida is part of the Northern Hemisphere club — it has four seasons, too.
As for the increase in daylight hours, just don’t expect it to happen overnight. And just to put the current condition in perspective: today’s paltry supply of sunlight is exactly balanced out by a bounty of sunlit (it’s longest day) on the southern side of the globe. At high noon today, the sun will be shining down directly on the Tropic of Capricorn, but for only one day, before starting its 6-month journey north to the Tropic of Cancer on June 21st.